SU1076464A1 - Method for heat treating permanent magnets - Google Patents

Abstract

METHOD OF THERMAL TREATMENT OF PERMANENT MAGNETS, including heating up to 1280 + 10s at a speed of 100-15 ° C / H, exposure and subsequent cooling at a speed of 50200 C / min to BOO + U C in a magnetic field with a strength of at least 160 kA / m, subsequent cooling in air to room temperature and a two-stage tempering at 620110, and characterized in that, in order to increase the maximum magnetic energy and coercive force of the source magnets, after two-stage tempering, additional cold treatment is performed at a temperature up to 10-15 minutes and double tempering at 550-570 ° C with a charge. within 1.5-2 hours each. (Ls

Description

35 4

but

four

The invention relates to metallurgy, in particular to methods of heat treatment of cast permanent magnets, and more specifically to the technology of heat treatment of magnets made of alloys of the UNDK-24 type.

A known method of heat treatment of permanent magnets, including heating to 1250-J., Cooling in a magnetic field and tempering at 650-120 ° C, cooling at a rate of 0.5-1.5 C / min to SSO-SeO C with a holding time this temperature for 1-10 hours lj.

This method provides increased magnetic properties, reducing the duration of the process.

There is also known a method of heat treatment of permanent magnets, including heating to 1280 ± 10 ° C, holding at this temperature and cooling in a magnetic field, and heating is carried out at a speed of 15020 sec / h. Heating and holding are carried out in medium c. Og content 1-15% 2.

Parameters of permanent magnets: residual induction of 14050 Gs, coercive force of 980 Oe, maximum magnetic energy of 7.3-10 GSe.

The closest in technical essence and the achieved result to the proposed is a method of heat treatment of permanent magnets, including heating to 1280 ° C at a speed of 100-150 C / h, holding and subsequent cooling to a magnetic field of at least 160 KL / m at a speed of 50–200 ° C / min, followed by air cooling to room temperature, then a two-step tempering: heating to 620 ° C for 2 h, reducing the temperature to 8 h CZ.

The known method does not provide an increase in the maximum magnetic energy and coercive force of the source magnets.

The purpose of the invention is to increase the maximum magnetic energy and coercive force of the original magnets.

This goal is ensured by the fact that according to the method of heat treatment of permanent magnes, including heating up to 1280 ± 10 0 at a speed of 100-150 C / h, holding and subsequent cooling at a speed of 50-200 ° C / min to 600tlO c in a magnetic field at least 160 kA / m, subsequent cooling with JO-comdat air: temperatures and two-stage tempering; - at 620 ± 10 and 59btl6 ° C, after two-stage tempering, additional cold treatment is performed at temperatures from -195 to -200С for 1015 min and two times tempering at 550570 С with exposure for 1.5-2 h to each

To carry out four experiments (examples 1-4) with different batches of magnets, they are subjected to the following treatment: heating to speed, holding at a given temperature and subsequent cooling to an in-magnetic field of 160 L / m at a speed of 120 ° C / min, air cooling to room temperature; two-stage tempering - heating up to 620 s with an exposure for 2 hours, a decrease in temperature to 590 ° C and an exposure for 8 hours.

Example 1. From the obtained magnets take magnets with the best lumbar properties: the coercive force LН "45.4-50.2 kL / m, magnetic

(Зг - ЬНс

/ max

 19 energy

19.6 kJ / m.

The magnets are additionally subjected to cold treatment in liquid nitrogen at t-19BC for 15 min, and then two-time tempering at t 570®С and exposure for 2 h each. The measurements made give the following results: coercive force by induction bH, 49.3-54 kA / m Increase in magnetic energy (Br lHc) tx 20.1-21.6 kJ / m.

Example 2. A magnet with underestimated properties is taken from the same batch of the magnets obtained (coercive force by induction He6 36.638, 2 kA / m, magnetic energy (bHe) 13.5-14.9 kJ / m.

These magnets are treated with cold in liquid nitrogen at t -196 ° C for 12 minutes, then a double tempering at t 560 ° C and an SHUTTER for 2 hours each. As a result, the magnetic properties of the magnets increase: the coercive force by induction (rises to 4244.6 kA / m, magnetic energy

, 2-18.1 kJ / m I - Example 3. Select magnets with high magnetic properties

coercive force by induction, 4-46, 9 kA / m, magnetic energy, 15-19.2 kJ / m,

they are subjected to additional treatment in liquid nitrogen at t -195c for 10 minutes and two-time tempering: when heated to t 550 ° C and aged for 2 hours each. The results of the magnetic properties of magnetic magnets of this batch: coercive force by induction of bHe 44.9-49.3 kA / car НсУпаг magnetic energy of 19.0-20.1 kJ / Mi. П РИМ эр 4. Take a batch of magnets with properties that meet the requirements of GOST 17809-72 coercive force by induction bHj 40,5-.44,5 kA / m, magnetic energy g-nibwv. 18-19.1 kJ / m) and subjected to additional processing in liquid nitrogen at ±. for 1 hr as well. then double tempering: when heated to 56 and exposure for 2 hours each. The measurements give the following results of the coercive force on the induction of LH. 36.7-40.8 kA / m, magnetic energy 13.5-18.05 kJ / m. EXAMPLE 5. A batch of magnets with the properties: LH 41,446, 9 kA / m, magnetic energy (fer-j -Kvi8.15-19.3 kJ / m, is taken, subjected to their double tempering: heating to t 560s and a shutter speed of 2 hours each. Measurements of the magnetic properties of the magnets of this batch show heat treatment modes

Magnetic parameters mean that the coercive force is 41.3-46.5 kA / m, (ft-l bie / S18, 81 kJ / m. Thus, it is experimentally established that cold treatment is more than 15 minutes and up to 1-2 hours gives negative results. The results of testing the proposed method and the known one are presented in the table .. Thus, using the invention yields up to 21.6 kJ / m. The coercive force increases to 54 kA / m. Increasing the magnetic parameters by using the proposed method will reduce the coefficient return when using constant UNDK-24 alloy magnets and avoid the use of more expensive magnets through the use of UNDK-24 alloy permanent cast magnets (more common and cheaper). The approximate economic effect of using the invention in the national economy is 2300 rubles a year.

Heat treatment according to GOST 17809-72 plus cooling to T -196C for 15 minutes. Two holidays: heating up to T 570С, aging for 2 hours each

Heat treatment according to GOST

17809-72 plus cooling

lo during

10 min. Double vacation:

heat up and shutter speed

for 1.5 hours each

Heat treatment according to GOST 17809-72 plus cooling at T -196 ° C for 12 minutes. Double tempering: heating up to T 560С, holding for 2 hours each

Heat treatment according to GOST 17809-72 plus cooling at T -196 C for 10 minutes. Two holidays: heating up to T 560s and holding for 1.5 hours each

20.1-21.6 45.4-50.2 49.3-54

19.2-20.6 42.3-44.6 45.4-49.3

16.2-18.1 36.6-38.2 42-44.6

19.0-20.4 45.2-49.3 47.8-52.3

Table continuation

Claims (1)

METHOD FOR THERMAL PROCESSING OF PERMANENT MAGNETS, including heating to 1280 + 10 ° С at a speed 100-150 ° C / h, holding and subsequent cooling at a speed of 50-, 200 ° C / min to 600 ± 10 ° C in a magnetic field with a strength of at least 160 kA / m, subsequent cooling in air to room temperature and two-stage tempering at 620110 and 590 ± 10 ^о С, which is due to the fact that, in order to increase the maximum magnetic energy and coercive force of the original magnets, after a two-stage tempering is carried out by cold treatment at a temperature dopFlnitelno ot'-195 to -200 ° C for 10-15 min, and double tempering at 550-570 ° C _with delayed for 1.5-2 hours each. '' In ω a (P) .1076464